Harvest Goddess Game
During the first week of Spring, if you go to the left channel on your TV, and keep pressing left until the Harvest Goddess shows up, she'll let you play a guessing minigame that gives you prizes for a good amount of answers in a row. Good way to make money at the beginning of the game.PS. Can be used during any Year, but has to be the first week of Spring.

Obtain new seeds
By shipping 100 of the following crops, you can unlock new crops which will be sold at the Supermarket in the right season.NOTE: You do not have to ship all 100 crops in one season, just as long as your Shippping List reaches 100 for the crop.

Turning Soil to Normal without Wasting Energy
Let's say you messed up with your hoe, go get a fence log and deposit it on the messed up tile, then remove it. The tile should be back to normal. This also works with any objects you can deposit on the field (rocks, branches). Your character won't lose stamina/gain fatigue while doing this.